This invention relates to a combination flow control, shutoff and pressure relief valve and more particularly to such a valve that is well adapted for use in drip irrigation systems.
In various fluid distribution systems such as drip type irrigation systems it is necessary to control the flow rate and pressure of the fluid within fairly narrow limits in order to assure proper functioning of the system. For example, in many drip irrigation systems an optimum operating pressure level is around 15 psi, whereas the water normally supplied from existing waterworks systems may range from 40 to 80 psi. It was therefore necessary to provide a valve capable of reducing or regulating to a preselected level the pressure of water supplied to it so that drip emitters or other components in the attached system will operate properly. Moreover, it was necessary to provide a valve capable of providing substantially complete shutoff; of relieving any pressure surges originating at the supply source to prevent them from reaching the connected system; and also of preventing any over-pressurization in the system due to operator error, as could occur with a conventional adjustable regulator.
A general object of the present invention is to provide a combination valve that solves the aforesaid problems.
Another object of the present invention is to provide a control valve adapted for use with a drip irrigation system that will allow the pressure components in the system to be set at a preselected level despite the pressure of the water supply.
Another object of the present invention is to provide a small valve that will provide pressure controlling as well as full shut-off.
Yet another object of our invention is to provide a control valve capable of performing pressure control and full shutoff functions and which is particularly well adapted for ease and economy of manufacture.